With a growth of mobile internet services, data amount in a wireless communication network surges sharply, accelerating a demand for the bandwidth. In order to alleviate the congestion of a mobile cellular network, network operators need to deploy more base stations to improve the network capacity, but this will certainly increase the investment cost and maintenance cost. To solve such contradiction, more and more network operators have chosen a mobile data offloading method for offloading a portion of data in a mobile network to other available access techniques, as a supplementary to the mobile network. Currently, the main supplementary network technologies used for the mobile data offloading include WiFi (Wireless Fidelity, wireless fidelity), a home base station, and an IMB (Integrated Mobile Broadcast, integrated mobile broadcast), etc.
WiFi is a standard of WLAN (Wireless Local Access Network, wireless local access network), and is a communication network consisting of a wireless network card and an AP (Access Point, access point). The AP is referred to as a network bridge or an access point generally, which is a bride between a traditional wired local access network and a wireless local access network. Therefore, a UE (User Equipment, user equipment) with the wireless network card mounted may share resources of the wired local access network and even of a wide area network via the AP; the working principle thereof is equivalent to a HUB or a router with a built-in wireless transmitter. The wireless network card is a client device responsible for receiving signals transmitted by the AP.
The LTE (Long Term Evolved, long term evolved) is a kind of mobile communication network which is studied by manufacturers in the current 3GPP (3rd Generation Partnership Program, 3rd generation partnership program) organization actively, and is an evolved network of a UMTS (Universal Mobile Telecommunication System, universal mobile telecommunication system). The LTE aims to provide a low-cost network which can reduce the time delay, improve the user data rate, and enhance the system capacity and coverage. An air-interface of the LTE network is achieved by deploying an eNB (evolved Node B), and the air-interface transmission for a mobile service is achieved by a communication between the UE and the eNB.
In the existing LTE technique, data transmitted on the air-interface is carried on different RBs (Radio Bearer, radio bearer) according to information such as QoS (Quality of Service, quality of service) and the like, where a SRB (Signaling Radio Bearer, signaling radio bearer) is used for carrying an RRC (Radio Resource Control, radio resource control) message (i.e. an RRC signaling), and a DRB (Data Radio Bearer, data radio bearer) is used for carrying data. During the process and/or after the process when the RRC is established between the eNB and the UE, the eNB may configure one or more RBs for the UE for carrying different types of data.
When detecting an RLF (Radio Link Failure, radio link failure), the UE initiates an RRC connection reestablishment procedure, resulting in a time delay for data transfer.